This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. 3rd year medical student - doing his research rotation with mentor, Dr. Bastiaan Driehuys Research in asthmatics and small animal asthma models has indicated that airway constriction leads to regional differences in lung ventilation, which can manifest as ventilation defects. Though the defects are not uniformly distributed throughout the lung, current in vivo methods for assessment of lung function only allow for assessment of global changes. Therefore, these techniques are unable to characterize changes in regions of the lung that are most affected by the disease process.